As is well known to tradesmen, a chalk line is an indispensible tool for marking long, straight lines on relatively flat surfaces, with endpoints spaced much farther apart than is practical with a straightedge. The tool typically comprises a refillable metal or plastic case containing powdered chalk and a spool of string (e.g., typically about 18- to 50-feet of line). A hook ring on the outside of the case attaches to the free the end of the string. A rewind crank connected to the spool is located on the side of the tool for winding the line into the case when the mark is made. The case typically has one pointed end so that it can double as a plumb bob.
A user marks straight lines by snapping the taut string coated and/or impregnated with dyed chalk. In use, the tool may be shaken to distribute chalk evenly inside the case. Next, the chalked string is laid across the surface to be marked and pulled tight. If possible, this entails connecting the hook ring to a stationary object at one endpoint of the line and pulling the case away from that endpoint towards the opposite endpoint of the line. As the case is pulled away, chalked line is withdrawn from the case. When the second endpoint is reached, the line is pulled taut. The string is then plucked or snapped sharply to cause the string to strike the surface, leaving a straight line of chalk residue.
To function properly, the ends of the string must be pulled in opposite directions until the desired length and tension are achieved. Because the length of string frequently exceeds a person's arm span, and because the taut string must be plucked, one individual alone typically cannot use a chalk line, unless the free end can be secured to something. In some situations, a nail may be driven into a surface to secure the hook ring at the free end to an endpoint. However, in other situations nailing may be impractical, because, for example, the surfaces may be finished or comprised of a material (e.g., a non-wood material) that is not suitable for receiving a nail. By way of example and not limitation, a nail cannot easily be driven into masonry or tile.
What is needed is an easy to use, portable, reliable, cost effective tool for securing the free end of a chalk line flush with various surfaces, without damaging the chalk line or the surface to be marked, and while centering the line at the desired end point.
The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.